Platen press for working cardboard blanks



Oct. 14, 1941. H. BOBST 2,258,880-

PLATEN PRESS FOR WORKING CARDBOARD BLANKS Filed Jan. 22, 1941 2 Sheets-Sheet 2 N'VE,NTOR= HENRI 50557 BYM,%ZW%

ATTORNEYS Patented Oct. 14, 1941 PLATEN mass F01? w ORKING CARDBOARD LANKS {lenri Bobst, Prilly, near Lausanne, Switzerland Application January 22, 1941, Serial No. 375,398

In Switzerland February 27, 1939 4 Claims.

The object of this invention is to provide a platen-press for working cardboard blanks. Said press is of the type comprising a pair of endless chains, positively connected one with the other, placed in motion intermittently, said chains carrying between themselves bars which connect them transversely to the direction of their motion, so that said bars execute a motion of translation, each of them carrying grippers capable of gripping a blank of cardboard.

This press is characterized by such an arrangement of the bars and such a control of the chains that at each standstill of the latter, a bar is in a station where a blank to be worked is delivered to be gripped by the grippers carried by said bar, another bar in a station where a blank just gripped is in a position for being worked, and

another bar in a station where it abandons a V blank previously gripped and already worked.

The accompanying drawingsshow, by way of example, an embodiment of the press according to the invention.

Fig. 1 is a vertical longitudinal section of the press.

Fig. 2 is a section of the carrying bar at the point of a gripper.

Fig. 3 is a section on an enlarged scale, showing part of a chain and two carrying bars standing in a registering position.

Fig. 4 is a partial plan view of part of the chain of Fig. 3, at the point of one of the carrying bars, partially shown.

In the press as shown in Fig. 1, blanks are carried from a pile of blanks I, lying on the right in the drawings, to a pile of worked sheets 2, lying on the left, after having gone through the press and having been submitted therein to cutting and scoring operations, these various operations occurring in the following way:

The top blank of the pile l, gripped and carried to the left on the drawings and by a sucker reaches endless bands 3 continuously in motion in the direction of the arrow 4. Said bands carry away said blank, introducing it into grippers constituting, together with a carrying bar, a whole unit designated by 5 and which will be described in more detail hereinafter. Said bar, as well as other similar bars, is' disposed between two endless chains, one of which, 6, is shown here, the other being disposed in front of the plane of the drawings.

Just when a blank is being introduced, for instance blank I, the grippers, distributed at regular intervals on the whole length of the bar, said length being greater than the width of the blank to be carried thereon, are open and motionless, on account of the momentary standstill of the chains. These chains are simultaneously set in motion by toothed wheels such as 8, keyed on a coinmon'shaft Q. The blank introduced is registered by gauges'32 carried by an oscillating table l0 also described in detail hereinafter. Said table It) causes the opening of the grippers, when it is in the position shown on Fig. 2, and their closing, when it rocks in the direction of. the arrow l I.

Once this rocking has taken place, all the grippers of the bar grip the blank I and, by the displacement of the chains 6, the bar and the grippers are carried as far as 5', and the blank as far as 'I'. In this new position when the grippers are at a standstill, the blank is placed between a fixed upper platen l2 and a movable lower platen I3 of the press, the space it occupies lying between the two chains and being sufilciently high for leaving a free passage to the carrying bar carrying the blank.

The fixed upper platen carries a punch M for the cutting and scoring of the blanks. The reciprocating lifting and lowering movement of the platen l3, guided in any known manner in the base l5 of the press in a direction perpendicular to the plane of the punch, is controlled by toggle levers H6. A bar l1, a rod I8 and a lever I9 turning around an axis 20, are controlled under the impulse of a movement communicatedto the rod 2 I by a rotative member 22.

At each standstill of the chains, a blank is therefore at the station I, and the whole is arranged in such a way that the toggle levers lift the platen I3 and then apply it against the punch l 4, and then finally lower it.

Once this operation is completed, the chains are displaced again until the following carrying bar comes into station 5, for gripping a new blank, and until the bar which was formerly in 5 comes into 5, where it will maintain a blank in working position, whilst the already worked blank will be deposited upon the pile 2 on account of the contact of the bar whichis carrying it, with members 23 resulting in causing the opening of the corresponding grippers.

All the operations described above are of course effected automatically, on account of mechanisms connected between themselves. Such mechanisms are not necessary to show, as they are in the line of the constructor and may comprise any well known means.

It is to be noted-however that the adopted embodiment for controlling the toggle levers has special characteristics. The rotative member 22 being given a movement of continuous rotation, the members described have bcen'placed so as to allow the platen I3 of the press to keep a width with regard to the platen I2 which is near the widest possible width during a sumciently long time for allowing a carrying bar to pass from the station 5 to the station 5. In fact, the disposition of an intermediate rocking member I9 and the particular orientation of said member with regard to rod I8 which, in the position corresponding to the upper dead point of the crank 22 is almost in alignment with the pivot 20, results in that the movement communicated to the toggle levers is insignificant, during a displacement of a comparatively big arc of circle of the rotative member carrying the crank.

The chains 6 are on both sides of the space occurring between the platens I3 and I I where the cardboard is worked. They are passed therefore, backwards as well as forwards in regard to the drawings, outside of said space. They may, for instance, be made to slide in both said places on guides (not shown) holding them up so that the carrying bars may pass between the platens without touching either the upper plate, or the lower plate. However, for each working of the press, an uplifting of the bar which momentarily holds the worked blank, must be considered, otherwise the uplifting of the blank by the movement of the lower platen would result in a tearing or a shearing of the cardboard held by the bar. A support 24, integral with the platen I3 and rising therewith, is used precisely for lifting up the carrying bar during each working of the press and to carry said member to the desired position. The support 24 may be adjustable with regard to the height.

Now, this is how the grippers are connected ,to the bars and cooper-ate with the latter for carrying the blanks.

In the profiled bar 25 shown in Fig. 2, which is a section view of it at the point of a gripper, grooves such as 26 are provided, each of them being used for receiving an elbow-shaped lever 21, pivoted at one of its ends on pin 28, the other end having the shape of a beak 26 whose lower side cooperates with part of the section of the bar for gripping and supporting the blank I. A

spring 30 normally compels the gripper to close to this end.

In Fig. 2, the gripper is shown open, i. e. in the position it would have at station 5 in Fig. 1 and against the table III at rest. In this position, the opening of the gripper is produced by an adjusable abutment 3I on the table II), which lifts the gripper up from beneath. Besides this abutment, one of which is opposite each gripper, the table I0 carries gauges 32 placed between the grippers and entering corresponding grooves in the bar, for registering the blank 1. The blanks therefore can only be introduced into the gripper in a quantity authorized by the arrangement of said gauges. So, each blank will be caught by the grippers in a registered position in regard to the direction of movement and it is intended to secure, later on, the registered position required for carrying out the work of the press.

As stated above, the'table I0 can rock in the direction of the arrow II. It will effect this movement each time that the chains are set in motion and shortly before the chains are set in motion again. This rocking results in compelling the gauges 32 to withdraw and to leave free passage to the blank 1 and to allow the grippers to close again under the action of their springs, on account of the lowering of the abutments 3|. The table III will only assume its rest position shown in Figs, 1 and 2 each time a carrying bar will be stopped at station 5 for gripping a new blank.

It is evident that step may be taken for the registering of the blanks laterally.

The member 23 shown in Fig. 1 is an arm urged by an elastic member (not shown), said arm having certain of its parts adapted to bear against the grippers of the bars when they are passing this point, so as to open them in a way similar to that which has just been described and to make them discharge the blank they are retaining.

As seen above, the presence of the gauges 32 allows the blanks to register just when they are caught by the grippers of a bar. It is possible, however, that through a stretching of the chains or on account of looseness 01' the various links between themselves, the accuracy of the station 5' in regard to station 5 of a bar, will be insecure.

Figs. 3 and 4 show a means which secure an absolutely accurate registering of both these positions the one in regard to the other.

v To the movable platen I3 of the press is fastened a shelf 33 having comprising at least two gudgeons 34 with a cylindrical body, butwlth a conical extremity, intended to penetrate into corresponding cylindrical openings 35 of the carrying bars. Since at each standstill of the chain, i. e. at the moment when the grippers in which a new blank is introduced, are opened, the platen I3 rises, it may be seen that the simultaneous introduction of the gudgeons 34 into the openings 35 of the bar will register the position of the latter.

When said bar. has passed then from the position 5 to the position 5, it is compelled to cooperate with other gudgeons 36 intended to register again its position, but this time, not in regard to the members registering the blank, but in regard to the tools working the latter. It Is to be seen, therefore. that for a predetermined position of a blank in regard to a carrying bar whose grippers are gripping it, there will be a registered corresponding position of said elements in regard to the tools. In order to adjust this second position in the most accurate way, a possible displacement of the gudgeons 35 may still be provided, by means of adjusting screws 31. Thus, the accuracy of the work is secured independently of questions of looseness in the chains, which P rmits in particular the utilization of the press for the working of blanks previously printed.

A possible adjustment of the position of the gudgeons 34' might also be provided.

It is evident that the press could be actuated by means of eccentrics instead of by means of toggle levers. The latter however have given better results and prolong more easily the time of the parted position of the platens I2 and I 3 for allowing the passage of the carrying bars displaced by the chains, while controlling the working of the platen I3 by means of a rotative member 22 which is given an intermittent rotative movement. The toggle levers also impart a very powerful pressure Just when the crank can'ied by the rotative member 22 is passing to the high dead point, which is the position diametrically opposed to the position as shown'in Fig. 1.

The platen I3 will be preferably carried by four toggle levers and independent means of regulating the height of the latter may be provided, so as to allow an accurate regulating of the distribution of the pressure upon the whole surface to be worked.

The use of toggle levers has still another advantage, in view of the particularity of the machine, i. e. to utilizefor various sizes of blanks to be worked only the part of the tools extending behind the carrying bar on a length equal to the length of the blank to be worked measured in the direction of the carrying, which may lead, in the case of small sizes, to the utilization of the half, of a third, even of a fourth of the surface of the platens. By the use of the toggle levers, in this case the stress of jamming is avoided which, in the case of a control with rods, would take place as a result of the unbalance of the stresses in the vertical guidance of the movable part of the press.

The carrying of the blanks I from the pile I can take place as described, 1. e. blank by blank,

but it could also take place by means of a continuous feeding, i. e. a feeder in which the sheets are following each other at a distance smaller than their length, so that they would be momentarily placed on top of the like tiles.

What I claim is:

1. In a press having devices for working blanks, a pair of chains, bars attached to said chains and grippers associated with said bars, means to register one of said bars when a blank is being re ceived and means to register another bar when a blank is being worked, said means being operated simultaneously, a gauge adapted to arrest a blank adjacent the receiving gripper and means to close the receiving gripper during operation of said register means, whereby the blank is properly located with respect to the gripper and the gripper is subsequently located relative to said devices.

2. In a press having-devices for working blanks, a pair of chains, bars attached to said chains and grippers associated with said bars, means to register one of said bars when a, blank is being received and means to register another bar when a blank is being worked, said means being operated simultaneously, said means in each instance including a pin-and a recess, a gauge adapted to arrest a blank adjacent the receiving gripper and means to close the receiving gripper during operation of said register means, whereby the blank is properly located with respect to the gripper and the gripper is subsequently located relative to said devices.

3. In a press having a stationary and. a movable platen, a pair of chains, bars attached to said chains and grippers associated with said bars, means to register one of said bars when a blank is being received and means to register another bar when a blank is being worked, said means being operated simultaneously, both of said means being mounted to move in unison with said movable platen, a gauge adapted to arrest a blank adjacent the receiving gripper and means to close the receiving gripper during operation of said register means, whereby the blank is properly located with respect to the gripper and the gripper is subsequently located relative to said A platens.

4. In a press having devices for working blanks, a pair of chains, a bar attached to said chains and a gripper associated with said bars, a gauge and means to feed blanks against said gauge,

means for controlling said gripper and a common element for operating the gripper controlling means and for withdrawing the gauge out of the path of travelof said blanks.

HENRI BOBST. 

